TAILIEUCHUNG - Dịch vụ mạng thế hệ kế tiếp P1

THE EVOLUTION OF CIRCUIT SWITCHING The current circuit switched network concept has remained essentially unchanged from the original electromechanical Strowger exchange (see the Preface for an explanation of how this exchange came by its name). At its most basic level the telephone network comprises transmission paths and switching nodes. The design of a circuit switch is based on the ability to physically create a path (circuit) from one network element to another and to hold this path open for the duration of the interaction (call) | Next Generation Network Services Neill Wilkinson Copyright 2002 John Wiley Sons Ltd ISBNs 0-471-48667-1 Hardback 0-470-84603-8 Electronic 1 Circuit Switched Technologies THE EVOLUTION OF CIRCUIT SWITCHING The current circuit switched network concept has remained essentially unchanged from the original electromechanical Strowger exchange see the Preface for an explanation of how this exchange came by its name . At its most basic level the telephone network comprises transmission paths and switching nodes. The design of a circuit switch is based on the ability to physically create a path circuit from one network element to another and to hold this path open for the duration of the interaction call . The second role of circuit switching is routing . determining the path to take from the ingress point to the egress point in the network. This can be performed in multiple stages each switching stage being linked by transmission paths. In the Strowger exchange routing was performed on a step-by-step basis using the pulsed make and break signalling from the telephone dial to step electromechanical selectors. Figure depicts a simple scenario of an own-exchange call . a call that only involves one routing and switching stage . This is similar to what would have occurred in the second exchange opened in the UK. Called the official switch it was used as a private branch exchange by post office officials at the post office HQ. It can be clearly seen from this simple example how routing is taking place in a step-wise fashion and a physical path is being created at the same time. Clearly a more complex routing mechanism is required for national and international calls this is performed by multiple stages of switching and routing connected via transmission paths. In this way the hierarchical nature of the routing 4 CIRCUIT SWITCHED TECHNOLOGIES Figure Strowger routing scheme -10 000-line four-digit numbering and thus numbering plan local transit and international

TỪ KHÓA LIÊN QUAN
TÀI LIỆU MỚI ĐĂNG
TAILIEUCHUNG - Chia sẻ tài liệu không giới hạn
Địa chỉ : 444 Hoang Hoa Tham, Hanoi, Viet Nam
Website : tailieuchung.com
Email : tailieuchung20@gmail.com
Tailieuchung.com là thư viện tài liệu trực tuyến, nơi chia sẽ trao đổi hàng triệu tài liệu như luận văn đồ án, sách, giáo trình, đề thi.
Chúng tôi không chịu trách nhiệm liên quan đến các vấn đề bản quyền nội dung tài liệu được thành viên tự nguyện đăng tải lên, nếu phát hiện thấy tài liệu xấu hoặc tài liệu có bản quyền xin hãy email cho chúng tôi.
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.